Geology of the Grand Tetons


Grand Teton Park Geology

The youngest of the Rockies, the Grand Tetons are mountains that were born around 9 million years ago by violent seismic activity. Due to how these peaks were formed, there are no foothills barring the view of the craggy rocks and canyons of this wonderland.

About the Peaks

The Grand Teton, towering at 13,700 feet and the second highest peak in the state, dwarfs the others known as the Middle Teton and the South Teton peaks. Together the Teton Range raises over 7,000 feet from the valley floor to its east. The steep incline from the valley to the top of the peaks is a result of eroding Precambrian crystalline rocks and the dipping Teton fault.

About the Glaciers

Alpine glaciers in the Teton Range have grown and receeded over cooling cycles within the last 2 million years. The Falling Ice Glacier on Mt. Moran and the Teton Glacier on the Grand Teton are located on the peak's shady sides and moste likely results of a more recent ice age, from as recently as 5,000 years ago.

Cascade, Paintbrush, Garnet, and Death Canyons are examples of u-shaped valleys that were carved out by glaciers. Glacial moraines have formed lakes such as Phelps, Bradley, Taggert, Jenny, String, Leigh and Jackson.

What's in a name?

Jackson Hole used to be known as Jackson's Hole, a name given to the area by fur trappers and mountain men who had to enter the valley from the north due to the steep mountains that surround it on all other sides.

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